github.com/vpayno/adventofcode-2022-golang-workspace@v0.0.0-20230605190011-dbafed5593de/internal/day03/app.go (about)

     1  // Package day03 is the module with the cli logic for the application.
     2  package day03
     3  
     4  import (
     5  	"bufio"
     6  	"fmt"
     7  
     8  	"github.com/vpayno/adventofcode-2022-golang-workspace/internal/aocshared"
     9  )
    10  
    11  // Run is called my the gain function. It's basically the main function of the app.
    12  func Run(conf Config) error {
    13  	file, err := aocshared.GetFile(conf.inputFileName)
    14  	if err != nil {
    15  		return err
    16  	}
    17  
    18  	scanner := aocshared.GetScanner(file)
    19  
    20  	data, err := loadData(scanner)
    21  	if err != nil {
    22  		return err
    23  	}
    24  
    25  	prioritySum, err := getPrioritySum(data)
    26  	if err != nil {
    27  		return err
    28  	}
    29  
    30  	aocshared.ShowResult(prioritySum)
    31  
    32  	groupPrioritySum, err := getGroupPrioritySum(data)
    33  	if err != nil {
    34  		return err
    35  	}
    36  
    37  	aocshared.ShowResult(groupPrioritySum)
    38  
    39  	return nil
    40  }
    41  
    42  func loadData(file *bufio.Scanner) (rucksacks, error) {
    43  	data := rucksacks{}
    44  
    45  	for file.Scan() {
    46  		line := file.Text()
    47  
    48  		if line == "" {
    49  			continue
    50  		}
    51  
    52  		r := rucksack{}
    53  		err := r.addItems(line)
    54  		if err != nil {
    55  			return data, err
    56  		}
    57  
    58  		data = append(data, r)
    59  	}
    60  
    61  	return data, nil
    62  }
    63  
    64  func getPrioritySum(data rucksacks) (int, error) {
    65  	var result int
    66  
    67  	for _, r := range data {
    68  		priority, err := r.getSharedPriority()
    69  		if err != nil {
    70  			return 0, err
    71  		}
    72  
    73  		result += priority
    74  	}
    75  
    76  	return result, nil
    77  }
    78  
    79  func getGroupPrioritySum(data rucksacks) (int, error) {
    80  	var groupSum int
    81  	group := []string{}
    82  	sacks := [][]string{}
    83  
    84  	if len(data) == 0 {
    85  		err := fmt.Errorf("rucksack list is empty: %v", data)
    86  		return 0, err
    87  	}
    88  
    89  	if len(data)%3 != 0 {
    90  		err := fmt.Errorf("rucksack list length, %d, isn't evenly divisible by 3", len(data))
    91  		return 0, err
    92  	}
    93  
    94  	for i, r := range data {
    95  		if i%3 == 0 && i > 0 {
    96  			sacks = append(sacks, group)
    97  			group = []string{}
    98  		}
    99  
   100  		group = append(group, r.items)
   101  	}
   102  
   103  	sacks = append(sacks, group)
   104  
   105  	for _, group := range sacks {
   106  		// not handling the case where the number of rucksacks isn't evenly divisibleby 3
   107  		g1 := aocshared.SetFromSlice(aocshared.SplitString(group[0]))
   108  		g2 := aocshared.SetFromSlice(aocshared.SplitString(group[1]))
   109  		g3 := aocshared.SetFromSlice(aocshared.SplitString(group[2]))
   110  
   111  		c1 := aocshared.SetFromSlice(aocshared.SetIntersect(g1, g2))
   112  		c2 := aocshared.SetFromSlice(aocshared.SetIntersect(g1, g3))
   113  		c3 := aocshared.SetFromSlice(aocshared.SetIntersect(g2, g3))
   114  
   115  		c1 = aocshared.SetFromSlice(aocshared.SetIntersect(c1, c2))
   116  		c1 = aocshared.SetFromSlice(aocshared.SetIntersect(c1, c3))
   117  
   118  		for item := range c1 {
   119  			priority := getPriority(item)
   120  			groupSum += priority
   121  		}
   122  	}
   123  
   124  	return groupSum, nil
   125  }